Billions of years ago, when microbial life first emerged on Earth, our planet would have appeared purple from space. Armed with this knowledge, scientists now say we should be on the lookout for exoplanets tinged in a similar purple hue — a possible sign of extraterrestrial life. »11/13/13 7:20am 11/13/13 7:20am

Now known as one of the most inhospitable places on Earth, the giant arctic island of Greenland might actually hold the birthplace of all life on Earth. Yes, all life on Earth might well have sprang from Greenlandic mud volcanoes. »10/26/11 12:30pm 10/26/11 12:30pm

The Moon was long considered an essential stabilizing presence in the development of life on Earth. Without its satellite, the Earth would have tilted too much on its axis, making life impossible. But maybe the Moon wasn't needed after all. »8/10/11 11:00am 8/10/11 11:00am

Around 2.4 billion years ago, the ancestors of bacteria took over the oceans and began photosynthesizing, creating massive amounts of oxygen where before there had been barely any. This was the Great Oxygenation Event, which made all subsequent life on Earth possible. All life except . . . yeast. »8/09/11 1:33pm 8/09/11 1:33pm